Granular activated carbon (GAC) is used to treat a 95°F (555°R) exhaust stream (Q = 5,000 ft3/min) containing 1,000 ppm pentane (MW = 72). GAC sorbs pentane at 0.07 kg/kg GAC. P = 1 atm.
a) Calculate the minimum amount of GAC needed for a 1 hour run time, if there is no mass transfer zone (or, adsorption zone).
b) How much more GAC would be needed if a mass transfer (adsorption) zone were present, and accounted for 60% of the length of the carbon bed?